Anthelmintically active 2-substituted carbalkoxythioureidobenzene derivatives either unsubstituted at the 4- or 5-position or substituted with different substituents than those described and claimed herein are known in this art (for example, see South African Pat. Nos. 70/08706, 71/03073, 71/03144, and 71/03924; and Japanese Pat. No. 71/22058).